Manually operated nautical winches mounted on sail boats comprise a drum on which ropes connected to the sails are wound. They include a crank connected to the drum for rotating it. The manually operated nautical winches are provided with a crank head receiving socket shaped to receive the head of a crank. When the head of the crank is inserted in the head receiving socket, manual rotation of the crank winds the rope on the drum thereby raising the sail. However the weight of the sails requires a substantial effort so that the drum in manually operated nautical winches is rotated slowly and depending on the strength of the crew, the effort required may be too much. However there is an advantage in using a manually operated crank that rotates the drum slowly, because if the rope falls off the drum, the slowly rotating drum can be quickly stopped and the rope can be repositioned on the drum before it is frayed. If the rope is frayed or torn, a great deal of time, effort, and cost is required to attach another rope to the sail.
Of course if manually operated nautical winches are already in place on the boat they could be economically modified and provided with power. However if this is done the drum may rotate too fast so that if the rope falls off the drum, the rope can be chewed up by the winch before the winch can be stopped.